/*
 * DefaultInputHandler.java - Default implementation of an input handler
 * Copyright (C) 1999 Slava Pestov
 *
 * You may use and modify this package for any purpose. Redistribution is
 * permitted, in both source and binary form, provided that this notice
 * remains intact in all source distributions of this package.
 */
package com.pironet.tda.utils.jedit;

import javax.swing.KeyStroke;
import java.awt.event.*;
import java.awt.Toolkit;
import java.util.Hashtable;
import java.util.StringTokenizer;
import java.util.Map;

/**
 * The default input handler. It maps sequences of keystrokes into actions
 * and inserts key typed events into the text area.
 * @author Slava Pestov
 * @version $Id: DefaultInputHandler.java,v 1.2 2007-11-09 16:05:46 irockel Exp $
 */
public class DefaultInputHandler extends InputHandler {
    /**
     * Creates a new input handler with no key bindings defined.
     */
    public DefaultInputHandler() {
        bindings = currentBindings = new Hashtable();
    }

    /**
     * Sets up the default key bindings.
     */
    public void addDefaultKeyBindings() {
        addKeyBinding("BACK_SPACE",BACKSPACE);
        addKeyBinding("C+BACK_SPACE",BACKSPACE_WORD);
        addKeyBinding("DELETE",DELETE);
        addKeyBinding("C+DELETE",DELETE_WORD);

        addKeyBinding("ENTER",INSERT_BREAK);
        addKeyBinding("TAB",INSERT_TAB);

        addKeyBinding("INSERT",OVERWRITE);
        addKeyBinding("C+\\",TOGGLE_RECT);

        addKeyBinding("HOME",HOME);
        addKeyBinding("END",END);
        addKeyBinding("S+HOME",SELECT_HOME);
        addKeyBinding("S+END",SELECT_END);
        addKeyBinding("C+HOME",DOCUMENT_HOME);
        addKeyBinding("C+END",DOCUMENT_END);
        addKeyBinding("CS+HOME",SELECT_DOC_HOME);
        addKeyBinding("CS+END",SELECT_DOC_END);

        addKeyBinding("PAGE_UP",PREV_PAGE);
        addKeyBinding("PAGE_DOWN",NEXT_PAGE);
        addKeyBinding("S+PAGE_UP",SELECT_PREV_PAGE);
        addKeyBinding("S+PAGE_DOWN",SELECT_NEXT_PAGE);

        addKeyBinding("LEFT",PREV_CHAR);
        addKeyBinding("S+LEFT",SELECT_PREV_CHAR);
        addKeyBinding("C+LEFT",PREV_WORD);
        addKeyBinding("CS+LEFT",SELECT_PREV_WORD);
        addKeyBinding("RIGHT",NEXT_CHAR);
        addKeyBinding("S+RIGHT",SELECT_NEXT_CHAR);
        addKeyBinding("C+RIGHT",NEXT_WORD);
        addKeyBinding("CS+RIGHT",SELECT_NEXT_WORD);
        addKeyBinding("UP",PREV_LINE);
        addKeyBinding("S+UP",SELECT_PREV_LINE);
        addKeyBinding("DOWN",NEXT_LINE);
        addKeyBinding("S+DOWN",SELECT_NEXT_LINE);

        addKeyBinding("C+ENTER",REPEAT);
    }

    /**
     * add a action listener for a specific key stroke
     * @param keyStroke key binding to add
     * @param action action to perform if key is pressed.
     */
    public void addKeyBinding(KeyStroke keyStroke, ActionListener action) {
        Object o = bindings.get(keyStroke);
        if(o instanceof Map) {
            ((Map) o).put(keyStroke, action);
        } else {
            bindings.put(keyStroke, action);
        }
    }

    /**
     * Adds a key binding to this input handler. The key binding is
     * a list of white space separated key strokes of the form
     * <i>[modifiers+]key</i> where modifier is C for Control, A for Alt,
     * or S for Shift, and key is either a character (a-z) or a field
     * name in the KeyEvent class prefixed with VK_ (e.g., BACK_SPACE)
     * @param keyBinding The key binding
     * @param action The action
     */
    public void addKeyBinding(String keyBinding, ActionListener action) {
        Hashtable current = bindings;

        StringTokenizer st = new StringTokenizer(keyBinding);
        while(st.hasMoreTokens()) {
            KeyStroke keyStroke = parseKeyStroke(st.nextToken());
            if(keyStroke == null)
                return;

            if(st.hasMoreTokens()) {
                Object o = current.get(keyStroke);
                if(o instanceof Hashtable)
                    current = (Hashtable)o;
                else {
                    o = new Hashtable();
                    current.put(keyStroke,o);
                    current = (Hashtable)o;
                }
            } else
                current.put(keyStroke,action);
        }
    }

    /**
     * Removes a key binding from this input handler. This is not yet
     * implemented.
     * @param keyBinding The key binding
     */
    public void removeKeyBinding(String keyBinding) {
        throw new InternalError("Not yet implemented");
    }

    /**
     * Removes all key bindings from this input handler.
     */
    public void removeAllKeyBindings() {
        bindings.clear();
    }

    /**
     * Returns a copy of this input handler that shares the same
     * key bindings. Setting key bindings in the copy will also
     * set them in the original.
     */
    public InputHandler copy() {
        return new DefaultInputHandler(this);
    }

    /**
     * Handle a key pressed event. This will look up the binding for
     * the key stroke and execute it.
     */
    public void keyPressed(KeyEvent evt) {
        int keyCode = evt.getKeyCode();
        int modifiers = evt.getModifiers();

        if(keyCode == KeyEvent.VK_CONTROL ||
                keyCode == KeyEvent.VK_SHIFT ||
                keyCode == KeyEvent.VK_ALT ||
                keyCode == KeyEvent.VK_META)
            return;

        if((modifiers & ~KeyEvent.SHIFT_MASK) != 0
                || evt.isActionKey()
                || keyCode == KeyEvent.VK_BACK_SPACE
                || keyCode == KeyEvent.VK_DELETE
                || keyCode == KeyEvent.VK_ENTER
                || keyCode == KeyEvent.VK_TAB
                || keyCode == KeyEvent.VK_ESCAPE) {
            if(grabAction != null) {
                handleGrabAction(evt);
                return;
            }

            KeyStroke keyStroke = KeyStroke.getKeyStroke(keyCode,
                                  modifiers);
            Object o = currentBindings.get(keyStroke);
            if(o == null) {
                // Don't beep if the user presses some
                // key we don't know about unless a
                // prefix is active. Otherwise it will
                // beep when caps lock is pressed, etc.
                if(currentBindings != bindings) {
                    Toolkit.getDefaultToolkit().beep();
                    // F10 should be passed on, but C+e F10
                    // shouldn't
                    repeatCount = 0;
                    repeat = false;
                    evt.consume();
                }
                currentBindings = bindings;
                return;
            } else if(o instanceof ActionListener) {
                currentBindings = bindings;

                executeAction(((ActionListener)o),
                              evt.getSource(), String.valueOf(evt.getKeyChar()), evt.getModifiers());

                evt.consume();
                return;
            } else if(o instanceof Hashtable) {
                currentBindings = (Hashtable)o;
                evt.consume();
                return;
            }
        }
    }

    /**
     * Handle a key typed event. This inserts the key into the text area.
     */
    public void keyTyped(KeyEvent evt) {
        int modifiers = evt.getModifiers();
        char c = evt.getKeyChar();
        if(c != KeyEvent.CHAR_UNDEFINED &&
                (modifiers & KeyEvent.ALT_MASK) == 0) {
            if(c >= 0x20 && c != 0x7f) {
                KeyStroke keyStroke = KeyStroke.getKeyStroke(
                                          Character.toUpperCase(c));
                Object o = currentBindings.get(keyStroke);

                if(o instanceof Hashtable) {
                    currentBindings = (Hashtable)o;
                    return;
                } else if(o instanceof ActionListener) {
                    currentBindings = bindings;
                    executeAction((ActionListener)o,
                                  evt.getSource(),
                                  String.valueOf(c), modifiers);
                    return;
                }

                currentBindings = bindings;

                if(grabAction != null) {
                    handleGrabAction(evt);
                    return;
                }

                // 0-9 adds another 'digit' to the repeat number
                if(repeat && Character.isDigit(c)) {
                    repeatCount *= 10;
                    repeatCount += (c - '0');
                    return;
                }

                executeAction(INSERT_CHAR,evt.getSource(),
                              String.valueOf(evt.getKeyChar()), modifiers);

                repeatCount = 0;
                repeat = false;
            }
        }
    }

    /**
     * Converts a string to a keystroke. The string should be of the
     * form <i>modifiers</i>+<i>shortcut</i> where <i>modifiers</i>
     * is any combination of A for Alt, C for Control, S for Shift
     * or M for Meta, and <i>shortcut</i> is either a single character,
     * or a keycode name from the <code>KeyEvent</code> class, without
     * the <code>VK_</code> prefix.
     * @param keyStroke A string description of the key stroke
     */
    public static KeyStroke parseKeyStroke(String keyStroke) {
        if(keyStroke == null)
            return null;
        int modifiers = 0;
        int index = keyStroke.indexOf('+');
        if(index != -1) {
            for(int i = 0; i < index; i++) {
                switch(Character.toUpperCase(keyStroke
                                             .charAt(i))) {
                case 'A':
                    modifiers |= InputEvent.ALT_MASK;
                    break;
                case 'C':
                    modifiers |= InputEvent.CTRL_MASK;
                    break;
                case 'M':
                    modifiers |= InputEvent.META_MASK;
                    break;
                case 'S':
                    modifiers |= InputEvent.SHIFT_MASK;
                    break;
                }
            }
        }
        String key = keyStroke.substring(index + 1);
        if(key.length() == 1) {
            char ch = Character.toUpperCase(key.charAt(0));
            if(modifiers == 0)
                return KeyStroke.getKeyStroke(ch);
            else
                return KeyStroke.getKeyStroke(ch,modifiers);
        } else if(key.length() == 0) {
            System.err.println("Invalid key stroke: " + keyStroke);
            return null;
        } else {
            int ch;

            try {
                ch = KeyEvent.class.getField("VK_".concat(key))
                     .getInt(null);
            } catch(Exception e) {
                System.err.println("Invalid key stroke: "
                                   + keyStroke);
                return null;
            }

            return KeyStroke.getKeyStroke(ch,modifiers);
        }
    }

    // private members
    private Hashtable bindings;
    private Hashtable currentBindings;

    private DefaultInputHandler(DefaultInputHandler copy) {
        bindings = currentBindings = copy.bindings;
    }
}
